Michael Cesaro Posted February 13, 2023 Share Posted February 13, 2023 Hey guys, I’ve been trying to get my rear tank working again. As of right now I can only run fuel off of the front tank. When I flip the selector switch it stops pulling gas from the front tank but doesn’t start pulling it from the rear. I’m not sure what the issue might be here. Both sending units have been replaced, the selector valve has been replaced, and the selector switch has been replaced as well. Thanks in advance for any help. Link to comment Share on other sites More sharing options...
grumpin Posted February 14, 2023 Share Posted February 14, 2023 If you have electric fuel pumps in the tank, can you hear it running? Link to comment Share on other sites More sharing options...
Gsmblue Posted February 14, 2023 Share Posted February 14, 2023 If you have electric fuel pumps in the tank, can you hear it running? Hate to be the one to say it.. Replacing a part does not mean the new part works. Can you test the rear sender? Link to comment Share on other sites More sharing options...
mat in tn Posted February 14, 2023 Share Posted February 14, 2023 Hate to be the one to say it.. Replacing a part does not mean the new part works. Can you test the rear sender? I think you need to measure the voltage going to the selector valve. also double check all fuses. for some reason I think the selector switch gets power from a shared fuse on some models, but I cannot say for sure. you might study the wiring in documents page. Link to comment Share on other sites More sharing options...
Michael Cesaro Posted February 14, 2023 Author Share Posted February 14, 2023 Hate to be the one to say it.. Replacing a part does not mean the new part works. Can you test the rear sender? You’re right, and I’m thinking about checking it again, but just a little while ago my selector switch went out and it defaulted to the rear tank without me knowing and ran out of gas. So as far as I know the sending unit can work. Link to comment Share on other sites More sharing options...
Michael Cesaro Posted February 14, 2023 Author Share Posted February 14, 2023 I think you need to measure the voltage going to the selector valve. also double check all fuses. for some reason I think the selector switch gets power from a shared fuse on some models, but I cannot say for sure. you might study the wiring in documents page. Replaced all the fuses the other day, I’m going to buy a test light soon and check all the connections I can soon. Link to comment Share on other sites More sharing options...
ArdWrknTrk Posted February 14, 2023 Share Posted February 14, 2023 Replaced all the fuses the other day, I’m going to buy a test light soon and check all the connections I can soon. This image from the EVTM shows fuse 15 should be hot in start and run. The fuel system defaults to the rear tank if the selector valve solenoid is not energized by the brown/white wire. Sender switching is done by the switch in your dash. Hope this is helpful. Link to comment Share on other sites More sharing options...
81-F150-Explorer Posted February 14, 2023 Share Posted February 14, 2023 Is this a "3" port selector valve type, located on the frame? With one electrical wire going to it. If so the rear tank is the default tank and the front tank is the secondary. With no power at the selector valve it should default to the rear tank. If it isn't then you may have the hoses reversed at the valve. Link to comment Share on other sites More sharing options...
ArdWrknTrk Posted February 14, 2023 Share Posted February 14, 2023 Is this a "3" port selector valve type, located on the frame? With one electrical wire going to it. If so the rear tank is the default tank and the front tank is the secondary. With no power at the selector valve it should default to the rear tank. If it isn't then you may have the hoses reversed at the valve. Figure 2 on pg. 100 (above) seems to show a straight fitting and a 90° fitting. I'm not sure you could get them reversed? But you have a good point! Link to comment Share on other sites More sharing options...
81-F150-Explorer Posted February 14, 2023 Share Posted February 14, 2023 Figure 2 on pg. 100 (above) seems to show a straight fitting and a 90° fitting. I'm not sure you could get them reversed? But you have a good point! On my 1981 there is no 90 degree fitting and the hoses are just hooked up to the valve with hose clamps. So a reversal of the hoses is extremely easy. The 1983 should be identical if not very similar. Things did change with the in-tank fuel pump, but the 1983 with 302 should still be mechanical fuel pump only. (From the Factory anyway. ) Link to comment Share on other sites More sharing options...
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